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NBC News
February 21, 2015

This content comes from Closed Captioning that was broadcast along with this program.

>>>for the missing malaysia air flight enters the seventh day, a team in massachusetts, scientists are looking closely at this and could be called in to help. they have a skill set that few possess. but as nbc's stephanie gosk found out, locating wreckage down below could take a very long time.

>> reporter: june 1st
,
2009
,
air france
447 plunged into the atlantic where the water is more than a mile deep and the terrain more rugged than any on land. the search went phone two years.

>>it was likelying in the mountain fos a
shoe box
with a
flash light
.

>> reporter: they asked for help in massachusetts, scientists there have a
secret weapon
.

>>so this is kind of like an under water drone.

>>exactly, people are not in it, it is flying on its own, navigating on its own.

>> reporter: a robot submarine, capable of covering 25
square miles
in a single day. how do you figure out what is a rock, a fish?

>>yes, well, actually it will show fish and changes in terrain, also the grouping, if we send a lot of strong signals from one location then you would get an indication there is a lot of man-made objects there.

>> reporter: in may
2011
this was the image the sub captured, a very telling blur. they went back and took
high definition
photos. mark dannet looked at them first.

>>the first one i remember was a backpack on the bottom.

>> reporter: you found a backpack?

>>the celebration was yes we did find it. we'll come to a conclusion here.

>> reporter: but it was the scene of the tragedy.

>>yes, that is right.

>> reporter: the scientists hope the phone will ring. but the range of subs ready to find flight 370.

>>it is small, compact.

>> reporter: what they need is an identifiable area, a hay stack, to begin a
slow search
for the needle.

>>just like painting the wall or putting the grass it can be really boring, but it is the only way to get the job done and to be sure you give yourself every opportunity to find the aircraft. you don't want to miss it.

>> reporter: finding
air france
was a triumph not just of technology but of determination. the team is ready to do it